As a substrate processing apparatus for processing a substrate, a vertical batch-type substrate processing apparatus is used. The vertical batch-type substrate processing apparatus is configured such that a substrate holder for holding substrates in multiple stages is loaded into a reactor and a process gas is supplied into the reactor to process the substrates held by the substrate holder. In the vertical batch-type substrate processing apparatus, cumulative films deposited on members (e.g., a reaction tube, a substrate holder, etc.) constituting an inner part of a reactor are removed by executing a maintenance recipe. For example, Patent Document 1 discloses a technique in which a cleaning gas is supplied into a reaction tube to remove an attachment including a thin film attached to an inner wall of the reaction tube and the like. Patent Document 2 discloses removing a cumulative film deposited within a process chamber of a single-substrate-type substrate processing apparatus by executing a maintenance recipe on a condition that a thickness of the cumulative film reaches a threshold value.
Depending on a kind of a film formed on a surface of a substrate, it is sometimes a case that, in addition to the deposits adhering to members (e.g., a reaction tube, a substrate holder, etc.) constituting an inner part of a rector, a deposit adhering to an exhaust pipe is diffused into the reactor, thereby causing a contamination problem. Under the circumstances, an attempt has been made to efficiently remove the deposit adhering to the exhaust pipe. For example, Patent Document 3 discloses a technique in which an etching gas is allowed to flow into only an exhaust pipe to efficiently remove a byproduct adhering to an inner surface of the exhaust pipe.